// Copyright (c) 2013, Hannes Würfel <hannes.wuerfel@student.hpi.uni-potsdam.de>
// Computer Graphics Systems Group at the Hasso-Plattner-Institute, Germany
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//   * Redistributions of source code must retain the above copyright notice,
//     this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright
//     notice, this list of conditions and the following disclaimer in the
//     documentation and/or other materials provided with the distribution.
//   * Neither the name of the Computer Graphics Systems Group at the
//     Hasso-Plattner-Institute (HPI), Germany nor the names of its
//     contributors may be used to endorse or promote products derived from
//     this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.

#define MAX_24BIT_UINT ((1 << 24) - 1)

struct NodeData
{
	uint color;
	uint depth;
	uint next;
};

uint packFloat4IntoUint(float4 color)
{
    return (((uint)(color.x * 255)) << 24) |
		   (((uint)(color.y * 255)) << 16) |
		   (((uint)(color.z * 255)) <<  8) |
		     (uint)(color.w * 255);
}

float4 unpackUintIntoFloat4(uint compressedColor)
{
    return float4(((compressedColor & 0xff000000) >> 24) / 255.0f,
				  ((compressedColor & 0x00ff0000) >> 16) / 255.0f,
				  ((compressedColor & 0x0000ff00) >>  8) / 255.0f,
				   (compressedColor & 0x000000ff) / 255.0);
}

// pack the depth into the first 24 Most significant bits
uint packDepthIntoUint(float depth)
{
    return ((uint)(depth * MAX_24BIT_UINT)) << 8;
}

uint unpackDepthIntoUint(uint compressedDepth)
{
    return (uint)(compressedDepth >> 8);
}